Organic Matter Preservation in the Sediment of an Acidic Mining Lake
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- 作者：Christine Laskov ; Wulf Amelung ; and Stefan Peiffer
- 刊名：Environmental Science & Technology
- 出版年：2002
- 出版时间：October 15, 2002
- 年：2002
- 卷：36
- 期：20
- 页码：4218 - 4223
- 全文大小：107K
- 年卷期：v.36,no.20(October 15, 2002)
- ISSN：1520-5851
文摘
Sustainable management of acidic mining lakes requiresknowledge on the origin and reactivity of its sedimentaryorganic matter. We identified different pools of organic matter(OM) in the Fe-rich sediment (up to 35 wt %) of anacidic (pH 2.8) mining lake using 
13C-signals, C/N ratios,and the markers alkanes, lignin-derived phenols, andbenzenepolycarboxylic acids (BPCA). Additionally, a densityfractionation was applied to each sediment layer. Threefractions, aquatic (AOM), terrestrial (TOM), and lignite-derived(LOM) organic matter, were discriminated, of whichAOM comprises only a small fraction, with a minimum atthe sediment bottom. The terrestrial contribution tosedimentary OM is higher than that of AOM but still lowthroughout the sediment core, whereas lignite-derived OMconstitutes the major C-fraction, even in the uppersediment layers. The size of the carbon pools was quantifiedwith a mass-balance approach, in which the BPCAcontent was utilized as an estimate for the lignite fractionin combination with the 13C-signals of the three Cfractions. The largest amount of OM was found in theheaviest (>2.4 g cm3) of the three density fractions of thetwo upper sediment layers, which implies strong interactionwith iron hydroxides. Comparisons with C-oxidation ratesrevealed that besides the refractory origin of the OM, sorptivepreservation by solid iron phases controls C-reactivity inthe sediment and, hence, the internal neutralization capacityof the lake system.
13C-signals, C/N ratios,and the markers alkanes, lignin-derived phenols, andbenzenepolycarboxylic acids (BPCA). Additionally, a densityfractionation was applied to each sediment layer. Threefractions, aquatic (AOM), terrestrial (TOM), and lignite-derived(LOM) organic matter, were discriminated, of whichAOM comprises only a small fraction, with a minimum atthe sediment bottom. The terrestrial contribution tosedimentary OM is higher than that of AOM but still lowthroughout the sediment core, whereas lignite-derived OMconstitutes the major C-fraction, even in the uppersediment layers. The size of the carbon pools was quantifiedwith a mass-balance approach, in which the BPCAcontent was utilized as an estimate for the lignite fractionin combination with the 13C-signals of the three Cfractions. The largest amount of OM was found in theheaviest (>2.4 g cm3) of the three density fractions of thetwo upper sediment layers, which implies strong interactionwith iron hydroxides. Comparisons with C-oxidation ratesrevealed that besides the refractory origin of the OM, sorptivepreservation by solid iron phases controls C-reactivity inthe sediment and, hence, the internal neutralization capacityof the lake system.